The unique propagation characteristics of millimeter-waves, including the ability to penetrate obstacles like fog, dust, fabric, and light building materials make them candidates for detection, imaging and remote sensing under adverse conditions. Unlike ionizing radiation emitted through the use of X-ray imaging systems, millimeter-waves engender fewer safety concerns around humans and animals. Additionally, because humans and animals emit a natural radiation that includes a portion of the millimeter-wave spectrum, imaging systems designed to detect such radiation may identify objects, such as, for example, weapons and/or contraband hidden underneath clothing when such objects block the naturally emitted radiation. At least one benefit realized by detecting naturally-emitted (e.g., human) millimeter-wave radiation is that detection systems do not need to employ a radiation source/emitter when scanning for objects.
Low-level high-frequency millimeter-wave signals may also facilitate improvements in fields of communication, imaging, medial diagnostics, avionics, and/or radiometry. In some fields of interest, relatively high standards of repeatability and resolution are necessary to accomplish one or more tasks, such as scientific and/or industrial radiometry applications. Some devices currently employed to detect millimeter-wave signals include Schottky diodes as direct square-law detectors. However, to achieve a sufficiently low junction resistance for high-efficiency impedance matching at millimeter-wave frequencies, Schottky diodes are typically biased and/or implemented in conjunction with one or more amplifiers in an effort to minimize detection noise. In some instances that demand a low noise floor, multiple stages of pre-amplifiers are necessary, each currently having a cost in the thousands of dollars.